Cooling system for vacuum tubes



COOLING SYSTEM FOR VACUUM TUBES Filed Nov. 12, 1929 2 Sheets-Sheet l @QQQQQQ V IN V EN TOR.

@fza cfe a a @ufvw, 9 4 I ATTORNEY April 25, 1933- c. A. CULVER 1,905,811

COOLING SYSTEM FOR VACUUM TUBES Filed Nov. 12, 1929 2 Sheets-Sheet 2 i S 45%- w 4 -t--- D ME s 7 6 a E 7 5 IN V EN TOR.

(945014900 (1 @Mmzv,

\ cnABLEs aicuLvnm ornoivrnrmtn, mini Patented Apr. 25, 1933 on NEW YORK, N. Y; A conrorm'rronor DELAWARE cooL rne sYsTnM ronv noutmr'ru ans" Application filed Kovemberm, 1929. Serial No.- 106,549. i

My invention relates in general to electron discharge devices and in particular to the cooling of high power discharge devlces of the exterior electrode type.

It is an object of my invention to edectively cool the anode of an electron discharge device and simultaneously insulate it from the ground and associated apparatus. I

:A further object myinvention comprises producing a cooling system which is simple and compact andin which the-degree of cooling may be definitely and accurately controlled. V V

A further object contemplated by my 1nvention consists in providing a coohng system which is not subject to deterioration, eliminates corona. effects and does not clog In one form of cooling system for power tubes, a rubber hose is connected to the upper and lower portions of'a water jacket surrounding the anode of the tube and water 1s allowed to flow therethrough. Although this type of cooling is in quite general use, it is not entirely satisfactory, especially when very high voltages are employed on the anode, due to the fact that the water column cannot conveniently be made long enough to provide a sufficiently high electrical resistance to prevent loss of current at the operating voltage of the tube; Owing tothis current leakage, the rubber hose is often sub ect to electrolysis, whichcauses a deposit onthe inner wall of the hose and thus decreases the electrical resistance of the water column. In addition to these disadvantages, corona discharges occur and cause pinhole perforations, producing leaks in the hose and further result in gradually hardening the hose so that it develops cracks.

According to my invention, all of the above noteddisadvantages are eliminated by pro- 7 high specific heat and one which cannot cause any deterioration of the cooling system, is circulated by compress on and expanslon.

In the drawings accompanying and forming a part of this specification and in which OTA,",ASSIGNQRZ 'ro wrnnn nanroj V like reference numerals designate corresponding parts throughout:.

i Fig. 1 illustrates a parti lly sectioned view' of one embodiment of my cooling system.

Fig.2 is a view in section of a'portion of I the system taken on the line 2-2 of ig. ll

Fig. 3 is a partially sectioned view of an alternative form ot my cooling system. i Fig. 4L is a view invse'ction of a portionlof the cooling. system takenon th k ew t Fig. 3;

Refemiig p r rlri dFigs. 1 are 2, my invention essentiallyiconsistsof a re-,

frigeration plantutilizing an inert gas as the working medium. 'I'Tprovide a chamber 5,015; relatively large dimensions in order that the chamber mayizcontain at-all times sufiicient weightof the medium to properly function,

provided with a cover'6,to which is attached in a gas, tight mannerv a. flange adapted. to hold by 'means of the locks 4, usually provided for such'purposes,a high poweredth ermionic tube 11 This tube is of the type employing an external anode 2, formedjof metal an dcon taining'the usualfgrid'iandIfilament 2d, as

shown in Fig 2. A pump 13, which maybe of either the reciprocating or rotating type, is provided andconnected by a conduit 10, to the; upper portion, of zt he chamblerf5'. The outlet aperture of thepump,13, is connected by conduit .11, with sQm e' suitable type of radiator 17 ,the' outlet of which is connected by condiiit 11, throughjeiipansion or needle valvej l2, the lower portion of theicham ber 5; motor 15 isflpiiovided for operating the pum and e is coupled to the pump hea by means or an insulating coupling 14. There is provided on the shaft; of the motor 15, alsoa fan 16, malintaincddn a position to 'forceair' through-the radiator 17, to as sist in cooling the "medium. circulating there: in. 'Itwillbejseen that the chamber 5," the conduits 1 0 -and11,ithe pump 13,;radiator'17, and expansion valve12; constitute a closed fluid circulatory system for the'g'aseous coolingmediuin." Any-inertfgas m y be "placed in this system under a pressure of two' or three atmo pherfi$ preferably, although I prefer to utilize hydrogen as the working medium because it is not only inert chemically, but has a high specific heat, being approximately fourteen times that of air. 7 The amount of the cooling medium necessary to perform the cooling function-for any type of tube may be accurately determined and the pump operated at a speed sufiiciently high to handle the required amountin the required. time." Ofcourse, if desired, a' ooling Ine-i dium may be selected having a relatively'low point of vaporization and the compressionof the medium by the pump be carried to a point where the medium is liquefied in the radiator.v In this way, of course, advantage may be taken of the internal latent heat of the medium in cooling the anode. In this case the weight of the medium' circulated in a given time wouldbe reduced- 1. Referring'now particularly to Figs. 3 and 4, I have shown an embodiment ofmy device which in all respects is similar to that just described. with reference to F igsflyand 2, withthe exception that there is inserted in the chamber 5, a helical baflie plate or fin, which is attached to the inner wall of the chamber 5, bymeans of the strips 7 andS, and presents, as shown in Fig. 4, a central aperture through whichithe anode 2, of'the discharge tube extends. This in effect produces a whirling action of the circulatingmedium and tends toincrease the efiiciencyof the cooling of the anode. w, j' From the above'descri'ption it will be readily observed that the action of the pump l3, createsa relatively'low pressure in the'chamher 5, and a relatively high pressure inthe cooling radiatorl7 The cooled gaseous mediunfr,v therefore, expands through the'ex' pansion or needle valve 12, to absorb substantial' quantities 'ofih'eat fromthe anode and this thermal energy'is carried away by the cooling medium as it is moved by means of the pump to the radiator 17 where it is radiated. "It'will be observed that the entire cooling system, with the'exception of the motor, is m'aintained'at the anode potential and is therefore not subject tocurrent loss, corona effects, or electrolysis It will be further observed that as the cooling system is a closed conduit circuit, there will be no accumulation of materials which would tend to clogthe system "and that the system is simpleiand effective in operation. Obviously also the degree of'cooling may be'definitely and accu rately determined bytheirapidity with which the cooling medium is circulated through the system and this, of course, may be easily regulated by the speed of the motor. 1 Havingthus vice, I claim:

completely described my de pansion valve, a conduit connecting said chamber, pump, radiator and expansion valve to form a closed fluid circulating system, an inert gas constituting the sole cooling medium contained in said closed system, and means for operating said pump to cause a'circulation ofsaid gas in said "closed syst'cin.

2, A cooling system for electron discharge devices comprising, a chamber adapted to receive and enclose in a gas tight manner the anode of an electron discharge device, a baffle plate within said chamber and adapted to encircle the anode of said discharge device, a

pump, a radiator, an expansion valve, 'acon-* duit connecting said chamber, pump, radiator and expansion'va'lve to form a closed fiuid circulating system, 'an inert gas constituting the sole cooling medium contained insaid' closed system, and meansfor operating said pump to cause a. circulation of sald gas in said closed system.

a 1 Julianne A; curves. 1

1. A cooling systenifor electron discharge devices comprising, a chamber adapted to receive and enclose in a' gas tight manner the anode of an electrondi-schar'ge device, a heli- 

